What’s in the skies above Whitby

Saturn
Saturn

Jupiter now lies low in the evening twilight, bringing to an end its long reign as the night sky’s dominant planet.

There is one last ‘hurrah’ when it is briefly joined by both Mercury and Venus towards the end of May before being lost in solar glare.

More on this interesting planetary conjunction in a few weeks’ time. The moon lies nearby on May 12th.

Having reached opposition, Saturn is now at its best, taking over from Jupiter as main planetary interest.

Look for its pearly glow across in the E/SE before midnight, due south around midnight and to the SW post midnight.

Although twice as far away as Jupiter is from us, Saturn still appears quite conspicuous, brighter than Spica the fist magnitude star in Virgo located to its right. Observed through a telescope Saturn is a stunning spectacle, one which always draws gasps of awe, especially when viewed for the first time.

The glorious rings are now favourably orientated, a sight any modest telescope will easily reveal. Look carefully and you will discern the major gaps, notably the Cassini division. Several of Saturn’s moons should also be apparent as specks of light close by, the most prominent of which being Titan, which moves around Saturn roughly twice a month. The moon lies nearby on May 22nd.

Comet L4 Panstarrs is still visible as a binocular object passing through the northern part of the sky above the W pattern of Cassiopeia, spending May in the faint ‘crooked house’ outline of Cepheus. On May 13, the comet stands fractionally upper right of Er Rai, the star marking the apex of the ‘roof’. View around 10.30pm.

The eta Aquarid meteor shower reaches a peak in the early morning hours of May 6th with rates of 15-25 visible between the hours of 2-4am. Should you be awake and skies are clear, view in any direction but southeast as this is where Aquarius is rising. It’s a pity Aquarius is not higher in the sky at this time otherwise rates of 40-50 per hour would not be uncommon.

Incidentally this is one of two meteor showers associated with debris particles deposited over time by comet Halley, the other being the Orionids, which peak in late October.

The Lion Springs Forth

As evenings continue to grow lighter, constellation recognition becomes increasingly difficult for the observer and it is after 9.30pm before the sky is sufficiently dark to trace all the major groups visible.

By then Orion, our winter ‘signpost’ star pattern, is already sinking below the west horizon, the ‘hunters’ belt stars parallel to it.

Further round in the NW Aldeberan in Taurus will soon be lost in twilight glare, whilst higher still, arranged from SW to NW are the prominent stars:- Procyon, Castor, Pollux and brilliant Capella. All but the latter will eventually depart the spring sky.

Fortunately from our latitude one ‘signpost’ pattern; the Plough is visible all year (circumpolar) and during spring is located high overhead to the northeast. The spring sky contains yet another most useful seasonal star group, standing proud due south, the celestial Lion of Leo.

In mythology Leo was the lion raised by Hera - Queen of the gods. The Lion’s coat was said to be impervious to fire and metal weapons. In the first of his twelve labours, Hercules, whom Hera despised, was given the task of slaying the beast that was ravaging the region of Nemea. After trapping the lion in a cave Hercules clubbed the lion to death and in honour, Zeus placed both in the heavens.

Leo is a splendid constellation. The head and mane is marked by the distinctive stellar asterism known as the ‘sickle’, which resembles a backwards ‘question mark’. At the base of this arrangement shines Leo’s chief star, Regulus, faintest of the 1st magnitude stars visible in the night sky. Regulus sits almost on the ecliptic and as a consequence is sometimes joined in close proximity by the moon and planets.

On rare occasions it is actually occulted by these, Saturn being the last planet to do so. In antiquity; from 4000 to 2000 BC Regulus was counted as one of the four Royal stars, those bright stars nearest the position of the equinox’s and solstices. During this period Regulus was closest to the summer solstice position, but the effects of precession has over time moved this point away.

Check out Algieba, the orange star above Regulus within the sickle, it becomes a lovely double star when viewed with a telescope.

To the left of the sickle, a ‘triangle’ of stars depicts the hindquarters of Leo. A number of galaxies are visible just below the stars of Leo which under good seeing conditions may be glimpsed with a modest telescope. Wait until fully dark before trying.

Following the celestial Lion across the sky, Virgo is ranked second to Hydra in size and contains the first magnitude star, Spica which lies some 250 light years away. The planet Saturn is currently located to the left of Spica. According to one legend Virgo represents Demeter; mother goddess of Earth, whose daughter, Persephone, after being pierced in the heart by one of Eros’s love arrows, was forced to return to the underworld ruled by Hades, who had instantly fallen in love with Persephone. Hearing the cries of her daughter, Demeter searched the world over without success, cursing the ground so that no crops would grow. Eventually Demeter learned of the whereabouts of Persephone and begged Zeus to free her. However Persephone was only allowed to return to Earth’s surface for six months in the year – spring and summer, descending back down into the underworld for autumn and winter, a reflection of when Virgo is visible in the sky.

The area of sky both within and extending above the ‘bowl of Virgo’ is known as the realm of the galaxies, a window onto the wider universe. Through this we are looking toward the Virgo galaxy cluster, some 40-60 million light years distant and the more remote Coma galaxy cluster which lies within our next destination, Coma Berenices.

Although this constellation consists of just a smattering of stars, it is one of the original 48 constellations, said to represent the amber tresses of Queen Berenices II. She was sister too and wife of King Ptolemy III of ancient Egypt. Berenices vowed to cut off her beautiful hair and place the tresses in the temple of Venus on the safe return of her husband from war with the Assyrians. The King was victorious and the Queen duly kept her promise, but the tresses disappeared from the temple, according to the court astronomer, Conon, removed by Zeus himself, honouring the donor by placing them in the sky. Although inconspicuous this area of the sky is rewarding to explore with many pleasing cascades of fainter stars visible in a telescope or pair of binoculars. Modest sized scopes also reveal numerous faint smudges of light; galaxies in the Coma cluster, the light from which started the long journey to Earth long before dinosaurs even roamed the Earth!

Our final destination currently located over in the east is Bootes, pronounced Bo-eh-tes, home to the brilliant star Arcturus, whose name is derived from the Greek meaning “guardian of the bear”. According to legend Bootes was the son of Demeter and was rewarded for having invented the Ox driven plough with a place in the heavens.

Arcturus itself is the second brightest star visible from Britain and has a lovely deep amber hue. At a distance of just 37 light years, Arcturus is the nearest example of an orange giant star, being around 30 times greater in diameter, somewhat cooler and much older than our Sun. In the distant future our Sun will evolve into a star resembling Arcturus. Of the brighter stars visible in the sky, Arcturus has by far the greatest ‘proper’ or true movement as seen against the background sky, indeed Arcturus appears to move a distance equivalent to the Moons diameter every 1000 years. This is because it is plunging through the galactic plane, cutting across the path of the Suns trajectory as it orbits around the Milky Way. Initially Arcturus will appear even brighter in our skies, but thereafter will rapidly diminish in brilliance, and in a few thousand years will become just another anonymous face in the stellar crowd!

Until the end of May, clear skies!

The final open night at the Bruce Observatory, Whitby Community College, is on May 5th from 9pm.

The first of the Whitby and District Astronomical Society public star parties from the West Cliff, near Cook’s statue, is on May 18th from 9.30pm. All welcome.